In this paper we investigate speech recordings before and after speaker's drug-abuse treatment, and show that there is no statistically significant dependency between distortions of speaker's fundamental frequency and formants on the one side, and different groups of drugs and on the degree of drug intoxication on the other. Changes of the fundamental frequency are not regular and do not have a general nature. The main reasons for these changes are changes in the emotional state of speakers, rather than a drug addiction treatment. Exploring the effect of the duration of narcotic drugs usage on the speaker's fundamental frequency showed that voices of speakers with prolonged use of drugs of the heroin group tend to decrease the fundamental frequency by about 3% per year.

Index Terms: fundamental frequency, formants, drug intoxication, speaker